Predominant Pollen and Spores

Alder season varies greatly from year to year and can be the result of the effect of weather and cyclical patterns. The counts can reach high levels. The season can start from mid-March to mid-April and ends early to mid-June.

Ash season can start from the third week of April to early May and ends the third week of May to almost mid-June. High counts are observed. May cause allergic reactions.

Beech season can vary a great deal from year to year due to cyclical patterns and the effect of weather. Low counts are generally observed but moderate counts are possible in certain years. The season can start early to late May and end late May to mid-June. May cause reactions in highly sensitized individuals.

Very high birch counts are observed, the season can last almost two months and can start from mid-April to early May and end early to late June.

Cedars, junipers and yews can produce high counts from April to early May. There is a short season mid to late March. The main season can start from the third week of March to mid-April and end late May to the second week of June.

Elms have an early low season that can occur in March. The main season can start late March to early April in warm years like 2010 and 2012 but generally it starts around the third week of April. The main season can have very high counts. The season can end from the first week to last week of May. At these levels they are considered important allergens.

Heaviest counts for the grass season occur in June and July. Low and moderate counts are observed and the season starts the first to the last week of May and ends late September.

Hemlocks usually only produce low counts but rarely moderate counts can occur. The season varies a great deal from year to year due to the effect of weather and cyclical patterns. The season can start from mid-May to early June and end from the first to the second week of June.

Larch and tamarack can vary a great deal from year to year due to the effect of weather and cyclical patterns. Some years only low and sporadic counts are observed while other years moderate counts are captured. The season can start from the third week of April to early May and end early to late May.

Linden and basswood season can vary from year to year. The season can start around the first week of July and end the third week of July to early August. Mostly low counts are observed with the occasional moderate possible. Some years only sporadic low counts are observed. The variation in seasons is due to the effect of weather and cyclical patterns.

Maple season is affected by the weather in when it will occur and how much pollen will be released. In the warm years, like 2010 and 2012, the season started the second the third week of March.

Generally the season can start from early to mid-April and end mid to late May. Very high counts are observed and some species are known to cause allergic reactions.

Nettles occur only in low numbers. The season can start late June to early July and end late August to early September. They are considered important allergens due to their small size.

Oak season can vary from year to year due to the effect of weather. The season can start the third week of April to mid-May and end late May to mid-June. Moderate and high counts are observed. Some species are known to cause allergic reactions.

The season for the pine, spruce and firs lasts at least two months. Some very high counts are observed. The season can start from the second week to the third week of May and end the first to the third week of July. Very high counts are observed and they could be very important allergens for those individuals who are sensitized.

Plantains pollinate from late June to late September. The counts are mostly in the low range with an occasional moderate possible. This may cause allergic reaction in highly sensitized individuals.

Poplar, cottonwood and aspen season lasts well over a month. The season can start the 3rd week of March in warm years like 2011 and 2012. Generally the season starts from the first to the third week of April and end early May to the last week of May. Some very high counts are observed and they can cause allergic reactions at these levels.

Ragweed only produces low counts. The season can start the third week of July to the second week of August and end late September to early October, or with a hard frost.

Walnuts are considered important in causing allergic reactions. The pollen season can start from early May to the third week of May and can end the second to last week of June.

The season can vary a great deal from year to year due to weather and cyclical patterns. Low and sometimes sporadic counts will be observed whereas an occasional year can produce moderate counts.

Willow season can produce moderate and high counts. The season can start from late April to early May in warm years like 2010 and 2012. Generally the season starts from the first to the second week of May and ends late May to the second week of June. They can cause allergic reactions at these levels.

Most of the significant counts of alternaria are found from mid-June to the end of September.

Significant counts of aspergillus occur throughout the whole counting season with high counts occurring from late May to early October.

Boletus season is from mid-June to mid-October and very high counts can occur. Considered an important allergen.

Botrytis counts are very sporadic. They can occur in the moderate ranges from late April to October.

Moderate and high counts of caloplaca are observed from April to early October. The counts are very sporadic.

Cladosporium is found throughout the whole counting season. The highest counts are observed from late March to early October.

Very high counts of coprinus are observed. Season is from mid-May to late fall. Very high counts are observed from July to Mid-October. Considered an important allergen.

Diatrypaceae counts are very sporadic and vary throughout the whole counting season. They are not known to cause allergic reactions.

Moderate counts of epicoccum are observed from mid-July to early October.

Erysiphe, also known as powdery mildew, season is from late April to mid-October and we find significant counts during this period. Highest counts are mostly in the moderate range.

Fusarium counts are very sporadic throughout the whole counting season. The majority of the season occurs from May to mid-October with some high counts. It is known to cause allergic reactions.

Very high counts of ganoderma are observed from mid-June to late fall. Considered an important allergen.

Helicomyces counts fluctuate throughout the season with low to high counts from late April to mid-October.

Leptosphaeria season is the end of May to mid-October with great fluctuations in counts from day to day. This is probably due to the effect of weather. The significant counts are mostly in the moderate range.

Moderate counts of myxomycetes are observed from mid-June to late September.

Significant counts of penicillium occur throughout the whole counting season with high counts occurring from late May to early October.

Moderate counts of pithomyces are observed in August and September.

Moderate counts of polythrincium are observed from July to late September.

Uredinales or rusts produce low and moderate numbers from mid-May to mid-October.

Ustilaginales or smuts produce low and moderate counts from late May to mid-October.